I will try and answer the question , but feel free to correct me anybody.
On a tile provides a clean surface , less likely to have parasites/ diseases.
Also easy to remove ( I wouldn’t let make contact with air ).
I.e place a container into the tank let it fill up with water. Then still in the tank move the tile into the container.
Water params must be identical and stable , less shock to the eggs.
On a tile you can remove them at the 7-8 day mark , If I remember right the hatch at 10 days (at night)
If you don’t remove them the parents will protect them for a few days . At some stage they will snap and say hang on I am running out of room here , time for a snack.......
As for making money , LFS wouldn’t offer you that much , it’s more a labour of love.